#ifndef __QUEUE_H
#define __QUEUE_H

/*
 * Tail queue definitions.
 */
#define _TAILQ_HEAD(name, type, qual)                                                                                  \
    struct name                                                                                                        \
    {                                                                                                                  \
        qual type *tqh_first;      /* first element */                                                                 \
        qual type *qual *tqh_last; /* addr of last next element */                                                     \
    }
#define TAILQ_HEAD(name, type) _TAILQ_HEAD(name, struct type, )

#define TAILQ_HEAD_INITIALIZER(head)                                                                                   \
    {                                                                                                                  \
        NULL, &(head).tqh_first                                                                                        \
    }

#define _TAILQ_ENTRY(type, qual)                                                                                       \
    struct                                                                                                             \
    {                                                                                                                  \
        qual type *tqe_next;       /* next element */                                                                  \
        qual type *qual *tqe_prev; /* address of previous next element */                                              \
    }
#define TAILQ_ENTRY(type) _TAILQ_ENTRY(struct type, )

/*
 * Tail queue functions.
 */
#define TAILQ_FIRST(head) ((head)->tqh_first)

#define TAILQ_INIT(head)                                                                                               \
    do                                                                                                                 \
    {                                                                                                                  \
        (head)->tqh_first = NULL;                                                                                      \
        (head)->tqh_last = &(head)->tqh_first;                                                                         \
    } while (/*CONSTCOND*/ 0)

#define TAILQ_INSERT_HEAD(head, elm, field)                                                                            \
    do                                                                                                                 \
    {                                                                                                                  \
        if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)                                                       \
            (head)->tqh_first->field.tqe_prev = &(elm)->field.tqe_next;                                                \
        else                                                                                                           \
            (head)->tqh_last = &(elm)->field.tqe_next;                                                                 \
        (head)->tqh_first = (elm);                                                                                     \
        (elm)->field.tqe_prev = &(head)->tqh_first;                                                                    \
    } while (/*CONSTCOND*/ 0)

#define TAILQ_INSERT_TAIL(head, elm, field)                                                                            \
    do                                                                                                                 \
    {                                                                                                                  \
        (elm)->field.tqe_next = NULL;                                                                                  \
        (elm)->field.tqe_prev = (head)->tqh_last;                                                                      \
        *(head)->tqh_last = (elm);                                                                                     \
        (head)->tqh_last = &(elm)->field.tqe_next;                                                                     \
    } while (/*CONSTCOND*/ 0)

#define TAILQ_INSERT_AFTER(head, listelm, elm, field)                                                                  \
    do                                                                                                                 \
    {                                                                                                                  \
        if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)                                               \
            (elm)->field.tqe_next->field.tqe_prev = &(elm)->field.tqe_next;                                            \
        else                                                                                                           \
            (head)->tqh_last = &(elm)->field.tqe_next;                                                                 \
        (listelm)->field.tqe_next = (elm);                                                                             \
        (elm)->field.tqe_prev = &(listelm)->field.tqe_next;                                                            \
    } while (/*CONSTCOND*/ 0)

#define TAILQ_INSERT_BEFORE(listelm, elm, field)                                                                       \
    do                                                                                                                 \
    {                                                                                                                  \
        (elm)->field.tqe_prev = (listelm)->field.tqe_prev;                                                             \
        (elm)->field.tqe_next = (listelm);                                                                             \
        *(listelm)->field.tqe_prev = (elm);                                                                            \
        (listelm)->field.tqe_prev = &(elm)->field.tqe_next;                                                            \
    } while (/*CONSTCOND*/ 0)

#define TAILQ_REMOVE(head, elm, field)                                                                                 \
    do                                                                                                                 \
    {                                                                                                                  \
        if (((elm)->field.tqe_next) != NULL)                                                                           \
            (elm)->field.tqe_next->field.tqe_prev = (elm)->field.tqe_prev;                                             \
        else                                                                                                           \
            (head)->tqh_last = (elm)->field.tqe_prev;                                                                  \
        *(elm)->field.tqe_prev = (elm)->field.tqe_next;                                                                \
    } while (/*CONSTCOND*/ 0)

#define TAILQ_FOREACH(var, head, field) for ((var) = ((head)->tqh_first); (var); (var) = ((var)->field.tqe_next))

#define TAILQ_FOREACH_REVERSE(var, head, headname, field)                                                              \
    for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last)); (var);                                        \
         (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))

#define TAILQ_CONCAT(head1, head2, field)                                                                              \
    do                                                                                                                 \
    {                                                                                                                  \
        if (!TAILQ_EMPTY(head2))                                                                                       \
        {                                                                                                              \
            *(head1)->tqh_last = (head2)->tqh_first;                                                                   \
            (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last;                                                    \
            (head1)->tqh_last = (head2)->tqh_last;                                                                     \
            TAILQ_INIT((head2));                                                                                       \
        }                                                                                                              \
    } while (/*CONSTCOND*/ 0)

TAILQ_HEAD(event_list, event);

#endif